K Band Receiving Front-end Chip With Polarization Switching

With the rapid development of ground mobile communication technology,the requirements for communication quality and scope are becoming increasingly high.High throughput low orbit satellite technology has received widespread attention,especially after the proposal of the "Star Chain" plan,which has sparked a wave of low orbit satellite internet construction.The main research content of this article is to propose a receiving front-end scheme with polarization switching function for RF reception in low orbit satellite communication systems.This thesis first introduces the basic theory and performance indicators of a low noise amplifier,analyzes the equivalent noise model of its two-port network and several common amplifier topologies.Then,based on the Win PL15-13 0.15 Ga As p HEMT craft,a low-power three-stage common source low noise amplifier is designed,which adopts an adaptive bias structure.The entire low noise amplifier chip only needs one power supply for positive electricity,simplifying the usage of the chip.In the operating frequency band of 17.5 GHz to 21.5 GHz,the noise figure is about 1.6 d B,the gain is above 23 d B,and the gain fluctuation in frequency band is controlled within 0.4 d B.The output P1 d B is about 4.2 d Bm,and the power is only 41 m W.The input and output return losses are both less than-10 d B,and have been verified through chip testing.At the same time,Lange couplers and FET switches were also simulated.Nextly,the RF reception front-end was designed.The two received RF signals were amplified through low noise amplifiers,coupled through Lange.and finally,one channel was selected to conduct using the FET switch,while the other channel was connected to the ground with a 50 ohm load.Two inputs correspond to one channel output,and the final EM simulation results show that the small signal gain is greater than 17 d B,the noise is less than 1.6 d B,and the gain flatness fluctuates below 0.7 d B in the frequency band.The isolation degree between the two channels is greater than 40 d B,and the phase balance degree is less than 2°.From the simulation results,it is in line with the expected goal,with good performance and practical application capability.